Build a prototype

Now that you have an early prototype as a proof of concept, you may want to
build a few more that is more robust than using a breadboard or protoboard.
In this section, we'll walk you through making your own custom boards.

Note: There are many online resources available that go into much more detail. If
you have any questions, let us know on
Google's IoT Developers on G+.

Designing your board (PCB)

Building a custom printed circuit board (PCB) for your prototype enables you to
begin testing your app using the components and mechanical layout that are more
representative of your final design.

As you're designing your product, there are many considerations for component
and PCB design such as industrial design, functionality, cooling, and power.

Create a schematic

Begin by designing a schematic of your device. A schematic
defines the components in your design and how they connect together. Your
schematic will include the various power and I/O components connected to the
SoM.

Figure 1. A schematic with Eagle using open source libraries provided by
Sparkfun

Create a layout

The next step is to build a physical drawing for the PCB. This is where you
define the size and shape of the board, physical layout of where to place
the components, and how the connections (traces) wires are will be routed.

Figure 2. A layout and the resulting PCB

There are many resources online to get you started but here are some design
packages: